Cyrene was founded in 630 BC as a colony of the Greeks from the Greek island of Thera, traditionally led by Battus I, ten miles from its port, Apollonia (Marsa Sousa). Details concerning the founding of the city are contained in Book IV of Histories, by Herodotus of Halicarnassus. It promptly became the chief town of ancient Libya and established commercial relations with all the Greek cities, reaching the height of its prosperity under its own kings in the 5th century BC. Soon after 460 BC it became a republic. In 413 BC, during the Peloponnesian War, Cyrene supplied Spartan forces with two triremes and pilots. After the death of Alexander III of Macedon (323 BC), the Cyrenian republic became subject to the Ptolemaic dynasty.